1. Field of the Invention
The present invention relates to a copying method and a copying apparatus for obtaining collated duplex copies from simplex documents preferably executed when obtaining duplex copies collated in the page sequence from a plurality of simplex documents.
2. Description of the Prior Art
In a copying apparatus, when it is desired to obtain duplex copies (copying papers duplicated on both sides of the sheet) from a plurality of simplex documents, two methods are known, that is, the method of copying from the final page of the original documents, and the method of copying from the first page thereof.
When copying from the final page, it is necessary to alter the copying method between the documents in an even number and the documents in an odd number. When the number of documents is an even number, the original side of the simplex documents is sequentially copied on both side of the copying paper, and the completely collated duplex copies are obtained. On the other hand, when the number of documents is an odd number, if the original side of the simplex documents is sequentially copied on both sides of copying paper the same as in the method of copying even-numbered documents, the other side of the copying paper on which the first page of the original document is copied on one side is a blank page, and the pagination of the duplex copies is deviated. Accordingly, the operator of the copying apparatus counts the number of documents, and enters either the odd number or the even number from the operation panel of the copier to select the copying method, or the documents are circulated before the copying operation to count the number in a copying apparatus furnished with a recirculating automatic document feeder (RADF) comprising a recirculating route in which the plurality of documents mounted on the document mounting member are sequentially conveyed, while being exposed in an exposure region, and are mounted again on the document mounting member.
Or in the method of copying from the first page of the simplex documents, it is not necessary to count the number of documents, but when feeding the documents into the copier, it is necessary to use, for example, an RADF in which the route of leading the document into the exposure region and the route of leading the document into the document hopper after exposure are the same.
When copying from the final page, manual counting of the number of documents is practically impossible when the number of documents is too many. Or when the RADF is designed to count the number of documents, the number of recirculating times of the documents increases, and it takes too much time when producing duplex copies, and the documents may be damaged.
Besides, in the case of copying from the first page, since the RADF having the identical route for leading the document into the exposure region and leading the document into the document hopper after exposure is used, it takes a long time to produce duplex copies.